The field of the disclosure relates generally to maintenance systems for use with electrical machines, and more particularly, to lockout systems for use in providing selective access to electrical machines.
Electrical machines are machines that use electrical power to perform one or more processes, such as processes used in manufacturing facilities. Such electrical machines are sometimes housed in cages or are installed in separate rooms to prevent operator injuries during operation of the machine. The cages or rooms typically include a door or gate that provides selective access to the machines, such as during maintenance of the electrical machines. For example, a typical cage includes a gate with a latch assembly that includes a handle operatively coupled to a latch bolt. When the gate is closed, the latch bolt extends into a latch strike within the gate or door frame and keeps the gate closed until the handle is moved to an open position, thereby retracting the latch bolt and allowing the gate to be opened.
To prevent potential injuries to maintenance workers and others accessing the cage or room, the cage or room may include a lockout circuit configured to power down the electrical machines within the cage or room when the gate is opened. The electrical machines will not be provided with power until the gate is closed and the latch bolt is extended. Known gates include features that allow the latch assembly to be “locked-open”, that is, the latch assembly is physically locked in an open position (i.e., the latch bolt is retracted) so that the lockout circuit cannot be inadvertently placed in a state where the electrical machines are powered while a worker is inside the cage. This may be referred to as “logged out” or “locked out”, to prevent inadvertent energization of the equipment. However, in certain situations, for example, upon detection of a malfunction within the lockout circuit, it would be beneficial to be able to physically lock a gate closed. As such, a need exists for improved lockout units that prevent access to machines both during standard operation and/or when the system or lockout unit experiences abnormal operating conditions, such as a malfunction.